A wide variety of techniques have been developed to prepare and analyze biological samples for analysis. Biological samples, e.g., tissue sections or cells, can be mounted on microscope slides for diagnostic purposes. The biological samples are often treated with one or more substances (e.g., dyes, reagents, etc.) to add color and contrast to otherwise transparent or invisible cells or cell components. The treated biological samples are often covered with coverslips to avoid contamination of the biological samples and to permit long-term archiving of the slides.
Automated coverslippers can be used to automatically place glass coverslips on specimen-bearing microscope sides. For example, automated coverslippers often pick up a coverslip from a stack of coverslips and place the coverslip onto a specimen-bearing slide. Unfortunately, automated coverslippers can pick up more than one coverslip because coverslips frequently stick together due to static forces, vander waal forces, or moisture between adjacent coverslips. This may result in two or more coverslips being mounted on a slide. It may be difficult to remove the excess coverslip(s) from the slide. If the automated coverslipper attempts to transport stuck-together slides, coverslips may drop resulting in loose coverslips in automated processing equipment. The loose coverslips can result in damage and/or malfunction of the automated processing equipment and may result in “downtime” for maintenance. Unfortunately, automated coverslippers are not capable of accurately counting coverslips during handling.